President
Bill Clinton nominated Lynch to the
U.S. Court of Appeals for the First Circuit on September 19, 1994, but the
United States Senate never voted on the nomination. Clinton renominated Lynch on January 11, 1995, to fill the seat vacated by Judge
Stephen Breyer, who was elevated to the
Supreme Court of the United States on August 3, 1994. The
American Bar Association's
Standing Committee on the Federal Judiciary, which rates judicial nominees, unanimously rated Lynch as "well qualified" (the committee's highest rating). She was confirmed by the Senate on March 17, 1995, by a
voice vote, and received her commission on the same day. She assumed
senior status on December 31, 2022. In
Crosby v. National Foreign Trade Council (2000), a unanimous Supreme Court affirmed this ruling, agreeing that state statute was "invalid under the
Supremacy Clause of the National Constitution owing to its threat of frustrating federal statutory objectives". In 2006, Lynch found that trading a gun for drugs constitutes a "use" of a gun for purposes of a criminal law against using a firearm in relation to drug trafficking. Her ruling was later abrogated by the Supreme Court's decision in
Watson v. United States (2007). In
Massachusetts v. United States Department of Health and Human Services (2012), Lynch joined a unanimous panel in holding (in an opinion written by Judge
Michael Boudin) that the
Defense of Marriage Act (DOMA) was an unconstitutional violation of the
equal protection principles of the
Fifth Amendment, because it denied to same-sex couples the federal benefits enjoyed by opposite-sex couples. On October 19, 2021, Lynch wrote the majority opinion that upheld Maine's
vaccine mandate for health care workers. The Supreme Court refused to review that decision. ==Awards and honors==